WASHINGTON (AP) — An appeals court has ruled that President Donald Trump must seek approval from Congress to build his proposed White House ballroom, saying construction must stop.

The U.S. Court of Appeals sided with historic preservationists who sued to stop construction. The court said it would stay its own ruling for two weeks to allow the administration to appeal to the U.S. Supreme Court.

“Whether or not a massive ballroom should be constructed is for Congress to decide and is not a matter for Executive self-help,” the court wrote.

“This holding has nothing at all to do with whether the proposed ballroom is desirable, or not, as a matter of policy. This ruling does not even necessarily mean that the Defendants may not ultimately construct the ballroom.

“What it does mean,” the court continued, “is that the Defendants may not do so during the district court’s expeditious litigation without securing Congress’s authorization, as the Constitution and laws require.”